looks like an interesting challenge.

The value should be static, at the time of creating record on table

For dates it uses range feature, so, you can split it by months, year (I suppose)

and move the whole bunch of records including indexes to another databse

While we moved our application to AWS, and we have some data, which we need to keep for a while. With this feature, we can move old data to a cheaper storage.

I believe the ability to move to a cheaper storage is mostly the case. Another option is that some table is too big, and someone would like to split it to be stored in multiple different databases, together with the indexes.